Current-perpendicular-to-plane giant magnetoresistive element, precursor thereof, and manufacturing method thereof

Abstract

Provided is a precursor of a current-perpendicular-to-plane giant magnetoresistive element having a laminated structure of ferromagnetic metal layer / nonmagnetic metal layer / ferromagnetic metal layer, the precursor having a nonmagnetic intermediate layer containing a non-magnetic metal and an oxide in a predetermined ratio such that the distribution thereof is nearly uniform at the atomic level. Also provided is a current-perpendicular-to-plane giant magnetoresistive element having a current-confinement structure (CCP) which has: a current confinement structure region made of a conductive alloy and obtained by heat-treating a laminated structure of a ferromagnetic metal layer and a nonmagnetic intermediate layer at a predetermined temperature; and a high-resistance metal alloy region containing an oxide and surrounding the current confinement structure region.

Description

TECHNICAL FIELD[0001]The present invention relates to a current perpendicular to plane-giant magnetoresistance (CPP-GMR; Current-Perpendicular-to-Plane Giant MagnetoResistance) element based on a ferromagnetic / non-magnetic / ferromagnetic three-layer thin film structure, a precursor thereof, and a manufacturing method thereof.BACKGROUND ART[0002]Current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) elements represent an important technique for the read heads of hard disk drives and magnetic sensors. For the non-magnetic spacer layer, a noble metal such as Cu or Ag, an alloy thereof, a laminate structure of a noble metal and an oxide such as Cu / ZnO / Zn or Ag / InZnO / Zn, or a current-confined-path (CCP; Current-Confined-Path) which is AlOx with Cu distributed therein has heretofore been used.[0003]The non-magnetic spacer layer in a current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) element serves an important role in determining the element's magnetoresistance rati...

AI Technical Summary

Benefits of technology

[0024]According to the current-perpendicular-to-plane giant magnetoresistance element of the present invention, when Ag / InZnO representing a conventional technique and AgInZnO representing the present invention are compared, the highest value of the magnetoresistance ratio is about 35% with Ag / InZnO, whereas a magnetoresistance ratio above 60% can be obtained with AgInZnO. Also, the techniques of Non-patent Literature 2 and Patent Literatures 1 to 3 cannot reduce the RA value to 0.2 Ωμm2 or less, but with AgInZnO the RA value can be reduced to 0.05 Ωμm2 by adjusting the Ag concentration. Further, the film thickness of Ag / InZnO is Ag (0.4 nm) / InZnO (1.3 to 1.75 nm), which makes a total 1.7 to 2.15 nm, whereas AgInZnO measures 1.2 nm, thereby enabling a reduction in the film thickness of the non-magnetic spacer layer. With a CPP-GMR element using a laminate structure of AgInZnO / InZnO as the non-magnetic spacer layer, a magnetoresistance ratio above 60% can be achieved within a range where RA=0.1 to 0.15 Ωμm2.

[0025]For conventional non-magnetic spacer layers with a laminate structure of a metal and an oxide, a plurality of sputtering targets are required. However, for the non-magnetic spacer layer according to the present invention, the number of sputtering targets required in a sputtering apparatus can be reduced by using a sputtering target in which a metal and an oxide are mixed in advance. Accordingly, improvements of production efficiency and a cost reduction can be expected.

Problems solved by technology

(1) The MR ratio is about 20 to 30% at the highest.

(2) The value of the resistance-area product RA of the element cannot be lowered to 0.2 Ωμm2 or less.

(3) The film thickness of the non-magnetic spacer layer 2 nm or more, which is relatively large.

Images